Setting control values for electronic image reproduction and processing in an electronic image scanner is generally accomplished by the input of information to a controller from an operator control panel and display. However, such arrangements necessitate an interface between the controls, the display and the controller, and between the controller and, for example, an image processing circuit. This requires a number of electrical connections of substantial complexity for the purpose of entering this control information. Buttons or switches must be provided, which upon actuation, provide an electrical signal to a control system indicating a desired condition. Generally, information regarding the control information or selection is also given to the operator simultaneously with its entry.
U.S. Pat. No. 4,162,408 to Hansen shows an apparatus for dynamically varying a reference threshold level when a mark or object is sensed moving across optics of the apparatus. U.S. Pat. No. 4,384,272 to Tanaka et al. discloses an image reading apparatus with movable marking members shaded to a predetermined density for determining the required reading area on a surface and the required illumination of the area. The marking member is detected by the image sensor. U.S. Pat. No. 4,147,295 to Nojiri et al. suggests a system for automatically correcting a threshold value of each bar in a bar code recognition system. The system comprises a movable card with a plurality of bars arranged in parallel on the card, a lens for converging the light reflected from each bar, and an image sensor which generates an image signal having a level corresponding to the light density of the reflected light. The threshold value with reference to which each bar width is discriminated is determined upon scanning the bars in order to enhance the recognition operation of the system. U.S. Pat. No. 4,724,330 to Tuhro suggests that an electronic input scanner may use a target for electronic acquisition and storage of registration information. U.S. Pat. No. 4,716,438 to Farrell discloses an arrangement in which machine control information is taken from a coded job sheet directed through a document handler.
It would be highly desirable to use a less expensive mechanical control information selection arrangement, in conjunction with the already existing imaging arrangement to provide a control information input to an image scanner.